Gas concentration detection method based on TDLAS

Abstract

The invention relates to a gas concentration detection method based on TDLAS, belonging to the technical field of gas detection. The method comprises the following steps: establishing oscillograms ofmodulation depth Dm and to-be-tested gas concentration, extracting four characteristic values of peak value range A, an average value m and a high order power mk of the average value m, an entropy h and a standard deviation s according to the oscillograms, constructing a generation function with a k value parameter, searching an optimal k value based on a dichotomy so as to obtain an optimal generation function with an optimal linearity degree, further measuring the sensitivity of the optimal generation function, and utilizing a curve, changing along the gas concentration, of the generation function with the highest sensitivity as a calibration curve for practical measurement. By virtue of repeated calculation, a measurement result approximates to a real concentration, and good linear relation and sensitivity are realized in the concentration dynamic range of 0-100%. The calibration curve obtained through inversion is applicable to different gases and absorbing peaks and has the optimal linearity degree and sensitivity aiming at different gases and absorbing peaks.

Description

technical field [0001] The invention belongs to the technical field of gas detection, and in particular relates to a TDLAS-based gas concentration detection method. Background technique [0002] Tunable semiconductor laser absorption spectroscopy (TDLAS) technology is a new gas detection method developed on the basis of the combination of diode laser and long optical path absorption cell technology by using laser wavelength modulation to pass through the characteristic absorption region of the gas to be measured. TDLAS technology has the unique advantages of non-invasive in-situ rapid on-line measurement and telemetry, as well as its high response rate, high precision, high sensitivity, multiple selectivity and fast response characteristics, so it presents a good value in gas detection and Application prospects. In the gas sensor based on TDLAS technology, the output wavelength of the semiconductor laser is very narrow (generally less than a few MHz), which is much smaller ...

AI Technical Summary

Problems solved by technology

[0003] In view of the above, the present invention aims at the problem of narrow dynamic range existing in measuring gas concentration based on TDLAS technology, and provides a gas concentration detection method applicable to the full concentration range and having high sensitivity at the same time

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